I can quilt a king size quilt on my 430- so the throat isn't small. But I don't think it would be very good on a frame. The frame itself would take up too much space and you wouldn't have much room, you'd be limited in the kinds of designs you can do, and the throat space.
The BSR doesn't need a frame. One of the fabulous things about it is it will keep your stitches even without needing a frame.